// Copyright (C) 2013 Google Inc. All rights reserved.
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// modification, are permitted provided that the following conditions are
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//
//    * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//    * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
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// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

#ifndef SKY_ENGINE_PLATFORM_GRAPHICS_GRAPHICSCONTEXTSTATE_H_
#define SKY_ENGINE_PLATFORM_GRAPHICS_GRAPHICSCONTEXTSTATE_H_

#include "flutter/sky/engine/platform/graphics/DrawLooperBuilder.h"
#include "flutter/sky/engine/platform/graphics/Gradient.h"
#include "flutter/sky/engine/platform/graphics/GraphicsTypes.h"
#include "flutter/sky/engine/platform/graphics/Path.h"
#include "flutter/sky/engine/platform/graphics/Pattern.h"
#include "flutter/sky/engine/platform/graphics/StrokeData.h"
#include "flutter/sky/engine/wtf/PassOwnPtr.h"
#include "flutter/sky/engine/wtf/RefPtr.h"
#include "third_party/skia/include/core/SkColorFilter.h"
#include "third_party/skia/include/core/SkPaint.h"

namespace blink {

// Encapsulates the state information we store for each pushed graphics state.
// Only GraphicsContext can use this class.
class PLATFORM_EXPORT GraphicsContextState final {
 public:
  static PassOwnPtr<GraphicsContextState> create() {
    return adoptPtr(new GraphicsContextState());
  }

  static PassOwnPtr<GraphicsContextState> createAndCopy(
      const GraphicsContextState& other) {
    return adoptPtr(new GraphicsContextState(other));
  }

  void copy(const GraphicsContextState&);

  // SkPaint objects that reflect the current state. If the length of the
  // path to be stroked is known, pass it in for correct dash or dot placement.
  const SkPaint& strokePaint(int strokedPathLength = 0) const;
  const SkPaint& fillPaint() const;

  uint16_t saveCount() const { return m_saveCount; }
  void incrementSaveCount() { ++m_saveCount; }
  void decrementSaveCount() { --m_saveCount; }

  // Stroke data
  const StrokeData& strokeData() const { return m_strokeData; }

  void setStrokeStyle(StrokeStyle);

  void setStrokeThickness(float);

  SkColor effectiveStrokeColor() const {
    return applyAlpha(m_strokeData.color().rgb());
  }
  void setStrokeColor(const Color&);

  void setStrokeGradient(const PassRefPtr<Gradient>);
  void clearStrokeGradient();

  void setStrokePattern(const PassRefPtr<Pattern>);
  void clearStrokePattern();

  void setLineCap(LineCap);

  void setLineJoin(LineJoin);

  void setMiterLimit(float);

  void setLineDash(const DashArray&, float);

  // Fill data
  Color fillColor() const { return m_fillColor; }
  SkColor effectiveFillColor() const { return applyAlpha(m_fillColor.rgb()); }
  void setFillColor(const Color&);

  Gradient* fillGradient() const { return m_fillGradient.get(); }
  void setFillGradient(const PassRefPtr<Gradient>);
  void clearFillGradient();

  Pattern* fillPattern() const { return m_fillPattern.get(); }
  void setFillPattern(const PassRefPtr<Pattern>);
  void clearFillPattern();

  // Path fill rule
  WindRule fillRule() const { return m_fillRule; }
  void setFillRule(WindRule rule) { m_fillRule = rule; }

  // Shadow. (This will need tweaking if we use draw loopers for other things.)
  const sk_sp<SkDrawLooper>& drawLooper() const { return m_looper; }
  void setDrawLooper(sk_sp<SkDrawLooper>);
  void clearDrawLooper();

  // Text. (See TextModeFill & friends.)
  TextDrawingModeFlags textDrawingMode() const { return m_textDrawingMode; }
  void setTextDrawingMode(TextDrawingModeFlags mode) {
    m_textDrawingMode = mode;
  }

  // Common shader state.
  int alpha() const { return m_alpha; }
  void setAlphaAsFloat(float);

  SkColorFilter* colorFilter() const { return m_colorFilter.get(); }
  void setColorFilter(sk_sp<SkColorFilter>);

  // Compositing control, for the CSS and Canvas compositing spec.
  void setCompositeOperation(CompositeOperator, WebBlendMode);
  CompositeOperator compositeOperator() const { return m_compositeOperator; }
  WebBlendMode blendMode() const { return m_blendMode; }

  // Image interpolation control.
  InterpolationQuality interpolationQuality() const {
    return m_interpolationQuality;
  }
  void setInterpolationQuality(InterpolationQuality);

  bool shouldAntialias() const { return m_shouldAntialias; }
  void setShouldAntialias(bool);

  bool shouldClampToSourceRect() const { return m_shouldClampToSourceRect; }
  void setShouldClampToSourceRect(bool shouldClampToSourceRect) {
    m_shouldClampToSourceRect = shouldClampToSourceRect;
  }

 private:
  GraphicsContextState();
  explicit GraphicsContextState(const GraphicsContextState&);
  GraphicsContextState& operator=(const GraphicsContextState&);

  // Helper function for applying the state's alpha value to the given input
  // color to produce a new output color.
  SkColor applyAlpha(SkColor c) const {
    int a = SkAlphaMul(SkColorGetA(c), m_alpha);
    return (c & 0x00FFFFFF) | (a << 24);
  }

  // These are mutbale to enable gradient updates when the paints are fetched
  // for use.
  mutable SkPaint m_strokePaint;
  mutable SkPaint m_fillPaint;

  StrokeData m_strokeData;

  Color m_fillColor;
  WindRule m_fillRule;
  RefPtr<Gradient> m_fillGradient;
  RefPtr<Pattern> m_fillPattern;

  sk_sp<SkDrawLooper> m_looper;

  TextDrawingModeFlags m_textDrawingMode;

  int m_alpha;
  sk_sp<SkColorFilter> m_colorFilter;

  CompositeOperator m_compositeOperator;
  WebBlendMode m_blendMode;

  InterpolationQuality m_interpolationQuality;

  uint16_t m_saveCount;

  bool m_shouldAntialias : 1;
  bool m_shouldClampToSourceRect : 1;
};

}  // namespace blink

#endif  // SKY_ENGINE_PLATFORM_GRAPHICS_GRAPHICSCONTEXTSTATE_H_
